Encrypting apparatus, encrypting method, decrypting apparatus, decrypting method, and storage medium

摘要

When content data is encrypted and recorded, the content data is block-segmented and chain-encrypted. At that point, an initial value is generated using content data of the same sector. When content data is an MPEG stream, an initial value is generated using unique information such as a header. Thus, it is not necessary to generate an initial value using a random number or the like. Thus, there is no loss in the data area. In addition, since content data varies at random, the secrecy of the initial value is high. In addition, since it is not necessary to provide a random number generator or the like, the circuit scale does not increase.